Issue 21233. Improve inlining strings into string interpolations.

pkg/analysis_server/test/services/refactoring/inline_local_test.dart

Index: pkg/analysis_server/test/services/refactoring/inline_local_test.dart
diff --git a/pkg/analysis_server/test/services/refactoring/inline_local_test.dart b/pkg/analysis_server/test/services/refactoring/inline_local_test.dart
index 7af239514772d3b5da51587169b7d246c7e4e4df..c78a7c3f21b1151e17adb84d4fc3388b40a146e6 100644
--- a/pkg/analysis_server/test/services/refactoring/inline_local_test.dart
+++ b/pkg/analysis_server/test/services/refactoring/inline_local_test.dart
@@ -94,6 +94,56 @@ process(x) {}
 ''');
   }
 
+  test_OK_intoStringInterpolation_raw() {
+    indexTestUnit(r'''
+main() {
+  String a = r'an $ignored interpolation';
+  String b = '$a bbb';
+}
+''');
+    _createRefactoring('a =');
+    // we don't unwrap raw strings
+    return assertSuccessfulRefactoring(r'''
+main() {
+  String b = '${r'an $ignored interpolation'} bbb';
+}
+''');
+  }
+
+  test_OK_intoStringInterpolation_string() {
+    indexTestUnit(r'''
+main() {
+  String a = 'aaa';
+  String b = '$a bbb';
+}
+''');
+    _createRefactoring('a =');
+    // validate change
+    return assertSuccessfulRefactoring(r'''
+main() {
+  String b = 'aaa bbb';
+}
+''');
+  }
+
+  test_OK_intoStringInterpolation_stringInterpolation() {
+    indexTestUnit(r'''
+main() {
+  String a = 'aaa';
+  String b = '$a bbb';
+  String c = '$b ccc';
+}
+''');
+    _createRefactoring('b =');
+    // validate change
+    return assertSuccessfulRefactoring(r'''
+main() {
+  String a = 'aaa';
+  String c = '$a bbb ccc';
+}
+''');
+  }
+
   /**
    * <p>
    * https://code.google.com/p/dart/issues/detail?id=18587